|
I get around 22mpg with mine and on the all freeway drive from Seattle to Michigan, i got 25mpg according to OBC and verified with fuel fill up vs. miles etc.
As for your bucking issue it could be a number of things. I chase a bucking issue on my wife's x3 for 2 months and replaced almost everything.
Transmission fluid filter (thought it was torque converter related)
Mass airflow sensor
primary O2 sensors
Cleaned Vanos sensors
Cam sensor
Crank sensor
Spark plugs
Coil packs
Eventually i found a video tucked away in the depths of youtube about the eccentric motor SENSOR. this sits under the valve cover, between the 2 cams and sticks up through the valve cover to its connector. It measures the cam angles once the eccentric motor rotates the exhaust cam. What happens is the sensor gets impregnated with oil over time and gives bad readings to the computer and motor causing the car to buck and kick. 3 BMW dealers and 2 independent shops couldn't figure it out. After replacing it for $130 and clearing the adaptations it never did it again.
|